The Ghost King at Hogwarts
by arabelladeveraux
Summary: Nico di Angelo has received a quest from no other than Hecate herself to help save the wizarding world from Voldemort. Arriving in a mysterious manner at number twelve Grimmauld Place, he faces scepticism. At Hogwarts, Nico finds out that saving their world with three curious teenagers hanging over your shoulder, isn't easy. (swearing) kinda OC Nico
1. Nico meets Hecate

**_A/N: This chapter is not edited, and will not be in the nearest future either. I don't really know if I'm going to continue writing this unless I get some reviews. And pretty please come with constructive criticism! English is basically my third language and I'm only 15 years old, so that would be really helpful._**

 ** _Did anyone feel Nico was too OC?_**

 ** _Should the next chapter be written in first person instead of third?_**

 ** _More describing text and less talking?_**

 ** _Should I write in a different way?_**

 ** _PLEASE lol, I'm desperate._**

 **CHAPTER 1: NICO MEETS HECATE**

The street was dark; the dim lights that lit the sidewalk hardly broke through the night's dark shadows. In places, the darkness was so thick that it seemed to be solid and tangible. A row of houses filled the street, all of them looking depressing, being old and withered away from age.

And in all that darkness stood a lonely boy. His dark features did not lighten up the place, but rather deemed to make it somehow darker. It was as if the shadows and darkness lingered to his body, thus making it hard to see his face. However, there was one thing the shadows could not hide, his aura. The boy had this sort of aura that gave away the feeling of death, misery, and sadness. What the boy radiated simply made you think of your worst nightmares.

He looked around, observing every nook and cranny, almost as he was looking for potential threats hiding around the corner. Just as the suspicious boy turned around, he came face to face with a beautiful woman. She radiated power and something that made you want to cower in fear. Her blonde hair stood it contrast with her dark skin, but it was not the unnatural combination that you took notice to, but rather her eyes: they glowed with a fiery rage that could not go unnoticed.

"Hecate, a pleasure as always", said the dark-haired boy. Although, it did not look like he was being completely truthful.

"Son of Hades, I do not come here for pleasures, and neither do I bring any. War is upon my people, my _other_ people, and they will possibly die, if not probably." He only scoffed as an answer.

"I presume you have called me here to fix the little problems your _other_ people have?" Hecate scowled, "you have presumed right about you fixing things, but however, these problems are not small. Not to them anyway. It's not often they stand upon a threat this big and deadly. By their standards, Nico, Voldemort is a big threat."

If possible, the shadows huddled closer to Nico, making him even harder to see. It was as if he _was_ the darkness and everything that comes with it. "I have heard much about this Voldemort from both my father and the random passing ghost. Not a lot of good have been said, especially not from Father. He has a special hatred stored away for people cheating death. Terrible paper work, he says." Nico paused a moment to think before he continued talking, "But I can't see how I will be of much help, I am not a wizard, and revealing my identity is out of the question. How can I possibly be of any assistance?"

Hecate seemed to stare at a house right across the street, not paying Nico any real attention. Nico knew Hecate was not one of the most reliable of the gods to keep the demigod children unharmed when aggravated, so he kept his mouth shut and waited for the goddess of magic to speak up. When nothing was said after a few minutes, Nico grew tired of waiting and decided to speak, "What do you want me to do, Hecate?"

Hecate did not hesitate before she answered, almost as if she was in a hurry. "I want you to help them. Infiltrate. Give them knowledge of the threat, but without giving away your secret." The ominous-looking boy was just about to cut her off, but the goddess continued talking before he had the chance. "How will you do this, you are probably wondering. I will give you magic, the type of magic they possess. However, you will not receive the training they have been going through, I will simply give you all the knowledge you need, if not more."

Nico was at loss for words. The goddess was simply just going to give him magical abilities? It seemed too good to be true. Abruptly, he started to get suspicious – was this only one of his father's tests? Maybe the only thing he was about to infiltrate was a group of monsters. No, he eventually decided, why ever would Hecate get involved with his Hades' mind games?

"So, how are you going to bless me with your magic? Zap me with your wand and say 'abracadabra'?" Nico asked rather condescendingly and ridiculing.

Hecate glowered at Nico, her eyes growing more menacing by the second. "Watch your tone, demigod", the goddess of magic said threating. Any other person, or demigod for that matter, would now have been on their knees begging for forgiveness, but not Nico. He stood tall, not really caring what she might do to him. When he would think about it later, Nico realized that maybe - just maybe, he actually wanted Hecate to punish him, to make him feel agony.

"I will transfer much of my information about spells and curses with godly magic. I assure you, it's much more reliable than waving a stick around." Nico thought he could hear some form of resentment in her voice. Were not they her beloved people?  
Deciding to let it go, he nodded as to tell her he was listening.

Without even a warning, Hecate had her hands on Nico's head and chanting words in Ancient Greek. He slightly jumped from the shock, but soon got over it seeing as the pain that started to develop overwhelmed him. What Nico felt was too difficult to describe, but there was this sort of warmth that flooded through the goddess over to the raven-haired adolescent.

Nico felt his head was about to explode from the heat, like his head was boiling over and brain matter running out of his skull. He could feel the magic leaving a piece of itself around his brain, then spreading around all over his body. He imagined this was what eating too much of the godly foods nectar and ambrosia would feel like.

After what felt like decades, the hands on his head was removed and the agonizing pain alongside with them.

His head was calming, but he could not feel any remotely new information in it. He was starting to wonder if Hecate's magic truly worked.

"I can't feel any difference", Nico said critically. "There's really no spells or anything in here", he said while pointing to his head.

"Do you doubt my power?" Hecate's voice was slightly raised and her tone was menacing. Sheepishly Nico answered, "No, of course not, my lady. I was only worried it didn't work."

She huffed in skepticism, not really believing his words. Neither should she.  
"Whatever, I have done my part, now you go do yours."

 ** _A/N: A bad ending, I know, but please bear (bare? lol) with me, it will probably get better._**


	2. Nico receives a not so warm welcome

**CHAPTER 2: NICO RECIVES A NOT SO WARM WELCOME**

 _ **A/N: Thank you all so much for your kind and helpful reviews, I appreciate it so, so much. And over 20 followers! Wow! I never in a million years would have thought of such a number, thank you so much, once again.**_

 _ **I am sorry to say that I won't update that often, only a couple times a month. I have a busy schedule due to mostly stress from school, tests, homework and social time with friends. I will try my best to update fast though.**_

 _ **And also, this I my first fanfic ever, so please don't be too harsh when you realize my story sucks, haha.**_

 **DICLAMIER: I do not own Harry Potter or Percy Jackson and the Olympians, or the follow-up series The Heroes of Olympus. The books and characters all belong to J.K Rowling and Rick Riordan. I am only a humble servant of the two.**

Nico had not really known what to expect when he got a letter saying that he was requested to meet outside of some or other house in England. The first thought that came was that it was a trap. Maybe Hades had something to do with it, he had assumed. It would not have been the first time his father demanded Nico to kill monsters or run errands for him, especially after the whole ordeal with Gaea. She left quite lot of mess behind, and the demigods had been cleaning it up ever since it ended a year ago.

Therefore, Nico had shadow traveled to the location written in the letter, expecting monsters to kill. Rather he met Hecate and was blessed with magic. Quite the difference from what he had expected.

 _linebreak_

When Hecate told Nico there was a hidden house between number 11 and 13, he started to wonder how he was supposed to get into a house he could not see. That problem was quickly resolved when the goddess of Magic simply lifted her hand and snapped her fingers, because just one second later he as standing in an abandoned hallway inside a house.

The inside of the house matched with the outside: withered and faded away from age and abandonment. The hallway was dark and dusty, even though it looked like someone had tried to tidy it up. They had failed miserably if he had to say it. Nico continued to walk quietly down it, blending in with the shadows, concealing himself from the potential threats that could reveal themselves at any second.

Looking warily around, he noticed several things. Some weird looking dead creatures hung up on the wall with shrunken heads and decaying flesh. Age-blackened portraits was also on the wall, hanging a bit crookedly. It was obvious that whoever lived here did not care much for the house.

He could feel something peculiar in the old-fashioned house as he came closer to the staircase. It felt suspiciously like something that should have died a long time ago. It felt like a broken soul, something that was very unnatural. Nico made his way to the stairs as if he was floating on the shadows, making no sound. He felt even more guarded than before because of the abnormal soulthat was just up the staircase. The raven-haired boy abruptly stopped when he heard loud voices coming from the doors to the right.

Nico could tell they were arguing about something, but the voices was too far away for him to hear, even though he has excellent hearing. Were these the people Hecate said he was to introduce himself to? The voices were adult ones, so he decided that, yes, it was. He let the shadows fall off him and walked over to the door, leaving the damaged soul for now.

He hesitated before knocking on the door. _'Hecate hadn't said a word about them. Do they even know I'm here to help? I don't even know what I'm supposed to do myself. I don't even know who these people are. How do I know they won't attack me...?'_ The thoughts flew through his head, leaving more questions than answers.

Finally, he came to the conclusion that the goddess would never put him in a situation like that. She could not expect from him to convince them all alone that he was there to help and guide them in some unknown way. Could she?

 _linebreak_

Oh, Styx was he wrong about Hecate. The second after the door was opened, a little less than a dozen sticks, both short and long, was pointed straight at him.

A man with a crazy eye that rolled all over the place made his way toward Nico threateningly, but Nico simply stepped a step to the left to avoid the weird man's magic stick. "OK, so they definitely didn't know about me coming", he mumbled under his breath.

"Who are you?" the man with the one eye nearly shouted at him, "How did you get in here!?"

He was unsure how to answer that question, he had not prepared any lies seeing as he thought all this was taken care of by Hecate.

When Nico did not say anything, the rest of the group studied the pale, but olive-skinned boy with inquisitive looks. They then proceeded to take a few steps closer to the mysterious boy with their hands tightly wrapped around their wands.

"Answer his question, _now_." Nico focused his eyes on the man who had spoken with such an aggressive voice. His slightly greasy, black, and curly hair stood unruly on his head, making him appear almost like a shaggy dog. For some reason he looked weirdly familiar. The Italian boy stared at him, trying to place his face.

The man with the eye darting back and forth rudely interrupted Nico's staring session by pressing the magical stick up to his throat. "How did you get in here?" he asked again, pronouncing every single word slowly to make it even clearer that Nico had to answer.

Nico quickly composed himself and swiftly lied, "I don't know. I was travelling about and all of a sudden I ended up in the hallway out here." He made a single gesture with his head toward the hallway. "I truly don't know. I don't even know where I am." Nico had always been good at lying, which was an especially convenient ability to have when you did it as often as Nico.

The same man that had advanced on the shadowy boy did not appear reassured by his words, but rather tenser than earlier. "Hmm, oh really, boy?" he snarled aggressively.

A man with a kind face in worn and washed-out clothes spoke up: "Moody, he's just a boy. How about we be a little more gentle?" The kind face matched his words.

The man with the crazy eye however did the exact opposite by, once again, sticking his pointy wand up to Nico's head. "No, Remus," he said while looking at the so-called Remus with a paranoia lighting up his eyes.

"How did he get in here? By accident?" Moody said the last part sounding disbelieving. "No way," he then continued. "He's probably a Death Eater! Look at him, with his dark demeanor and his scowling face. Let's check his arm; we have to check for the Dark Mark!" Moody's voice only got louder and louder, and his paranoid and distrustful look only increasing with it.

Remus chuckled slightly as though the (kind of) one-eyed man's behavior was an everyday occurrence for him. _'It probably is too'_ , Nico thought for himself.

"Okay, calm down, Moody. We'll check his arms, but how about we do it with little to no violence," he said not unkindly.

And to no surprise to anyone, Moody did not listen. He instead readied his wand, uttered a spell and just a second later, Nico was on the floor with a banging head and slightly stiff body.

Down there on the floor, Nico saw someone he had not noticed earlier, which was very odd; he could always sense somebody's soul or aura. _'Unless they are hiding'_. The man stood quietly in the corner with a conflicted look on his face. The man seemed to be very old with his long, white beard tucked into his robe. _Robes_ , those look even worse than the togas does. While Nico watched the man with the half-moon spectacles with fascination, several of the people in the room started to get the same paranoid voice like Moody had earlier. _"The spell is not working on him!"_ or _"how is he still moving"_ or _"He's not petrified!"_ Heard Nico faintly through the balls of air in his ears. _'Am I not supposed to be moving? What have you done to me?_ ' he wanted to ask them, but nothing came out from his mouth.

Nico looked back in the corner where the white-haired man stood, but he was not there anymore. Rather he was walking toward the group with a small smile on his lips. "This is an extraordinary thing we have just witnessed here, I think you all agree." Small grunts of agreement flew around the room. "I think that is an understatement, Professor Dumbledore. No one have ever escaped the spells of Mad-Eye," said the same man that Nico had an intense staring session with earlier on. ' _Professor Dumbledore, what are you doing in the corner of the room hiding in the shadows?'_

"Yes, very peculiar. Alastor is a great wizard, but somehow, a child managed to escape his powerful spells. Very peculiar," replied the professor with a twinkle in his eyes. He almost looked enthusiastic. Dumbledore turned to the son of Hades and said, "How about you tell me your name, dear boy?"

Nico was feeling unsteady, but managed to stand wearily up. He was feeling very apprehensive around all these people, especially Professor Dumbledore, but he answered nonetheless.

"Nico Di Angelo." It was a curt reply, but not unkind. Without even giving it a thought, the shadows came closer to, darkening him. The darkness gave him a sensation of security, and so he started to observe from the safety of his little bubble. Two flaming redheads was talking quietly a table, occasionally taking a quick glance at the secretive boy. A man with shoulder long, black, greasy hair and with pitch-black robes stared at him with such suspicion it almost made Nico flinch. Mad-Eye Moody was nowhere to be seen, which the king of ghost found strange. He would have thought the distrustful man would stay as close as possible to him.

Ignoring the black-haired man, Nico continued regarding the people around him. Remus and the shaggy-looking man was also having a discreet conversation, too quiet for Nico to make out their words.

Dumbledore's voice woke Nico up from his trance. "And exactly how, Nico Di Angelo, did you get in here? There are several spells and enchantments protecting this house from intruders like yourself." The son of Hades was unsure how to reply. Should he tell this strange man part of the truth or just make up an entire lie? Deciding to tell the old professor what he had told Moody, he answered. "I was only traveling when I suddenly felt something dragging me to this place. It happened in just a second; unexpectedly I was in the hallway out there. I then heard voices coming from behind the door and chose to see what it was. Not my smartest choice considering what happened after." Dumbledore made a small chuckle at that.

"I say we use Veritaserum," the man in the dark robes and greasy hair interrupted. "Now, Severus, isn't that a little excessive?" replied Dumbledore.

And just then, came the grumpy Moody stumbling through the door. "None of the defenses are broken, let's use the truth serum. I would like to ask that boy several things. Like why that Death Eater has a sword tucked under his shirt."

The wizards looked at Nico with dreadful looks, wondering why a wizard would ever need a sword. And more importantly, why a teenage boy would need one.

"Professor Snape," said the male redhead from the corner, his voice strained. "Would you be so kind to go get the Veritaserum?" Professor Snape answered with a curt nod and strode out the door.

Nico did not let it show, but inside, he was panicking ever so slightly. A truth serum? They could make him reveal all his secrets, all his _world's_ secrets, all in less than an hour.

"You wouldn't mind, would you Nico? We only want to make sure you're telling us the truth." Dumbledore said all this with the same unnerving twinkle in his blue eyes.

Nico scoffed, making the thought of him not telling the truth seem incredulous. "Of course, Professor Dumbledore. Totally understandable."

 _ **A/N: sorry for the short chapter, but it was a short one or not posting anything for a long time. My week had been exceptionally busy, but a have "fall-break" (sounds better in Norwegian lol) from now on, so I will get some writing done during that time.**_

 _ **And please come with constructive criticism! I have never really written a long story before, so I have no experience doing that.**_

 _ **Anything you want me to include in the next chapter? Tell me and I will consider writing it.**_

 _ **Thank you.**_

 **IMPORTANT! This is now written the 2nd of November, and I'm still not quite finished with the third chapter. It will come, no worries, but it might take a while longer. This is my final year to maintain my good grades, if not improve them, so writing is not my first priority. Maybe in a few weeks it's finished, but who knows. The beta I recently got has to look through it too, so yeah. PLEASE BE PATIENT! sorry**


	3. Nico and his secrets - PART 1 beta-ed

**This is the same chapter as the last one, but this has been edited by my amazing beta, so it's a lot better than it was. Nothing has changed but the overall look is much better, so I would advise you to read it :)**

 **And the next chapter won't come in the nearest time seeing as I have not really written it yet. But Christmas holidays are coming up, so I'll make sure I get some writing done then.**

 **o0o0oo0o0o0**

 **CHAPTER 3: NICO AND HIS SECRETS**

Nico was currently sitting in the middle of the room on a chair. All eyes were on the dark boy, which was making Nico uncomfortable. He had never really been good with people staring and judging him, even though he had lived with it for so many years. At camp some of them actually tried to keep it discreet, which was more than you could say about the wizards. These wizards were actually being quite understanding considering a teenager had just broken into their home, but the obvious staring was pissing him off. The magic folk were waiting impatiently for Professor Snape to come back with the truth serum. Nico hoped Snape fell down some stairs and died.

Piercing screams suddenly came from the hallway and Nico was instantly worried but the stick-waving people simply sighed in annoyance as if this was normal. Not seconds later the greasy-haired professor came through the door, hurtling towards the child of Hades, the Veritaserum in hand. Before Nico new it, Severus Snape was right in front of him. Snape pried the Italian boy's mouth open with his fingers unceremoniously and uncorked the serum. Nico was trying to pull his head back from the clear substance that was coming nearer and nearer but was failing miserably.

"Severus," said Dumbledore hastily, interrupting Snape's actions. The old man looked around at the wizards in the room while speaking. "I think it will be best if Nico and I speak privately."

Mad-Eye, unsurprisingly, took this very badly. He was just about to speak up and voice his disagreement but a firm look from Professor Dumbledore silenced him. Professor Snape was not too happy himself with Dumbledore's decision, but nodded grudgingly nonetheless and backed away from Nico.

"If all of you would be so kind as to leave the room," Dumbledore requested in a friendly manner. One by one, the wizards left by the only door in the dark room but not without a second glance at Nico.

'They fear me,' thought Nico sullenly. Even though it was understandable, he was tired of people judging him, being afraid of him at first glance. 'They do not even know me'. It made the depressed boy even sadder.

From the corner of Nico's eye, he saw the white-bearded professor with the dark green bottle in his hand, the one containing the clear potion. The Ghost King had not noticed Professor Dumbledore receiving the truth serum from Professor Snape and that made him worry. He was usually more attentive.

"I am Albus Dumbledore, the headmaster at Hogwarts School of Witchcraft and Wizardry," informed the professor as he walked over to the brooding boy. "I know plenty of magic Nico, and what I saw you do today is absolutely extraordinary. You are only a boy but somehow you managed to break into this house, accidently nonetheless, and without breaking any of the defensive spells surrounding it. This is not something to be taken lightly."

Even though the headmaster's words were grave and serious, the way his eyes shined with quiet excitement did not match his words.

Nico gave the aged man a calculating look. He did not seem judgmental, only curious, which was something entirely new for Nico.

The son of Hades continued examining the wizard, trying to figure him out. He got a better look at his appearance since the professor was no longer hidden in the dark. The old man was tall and thin with silver hair and beard so long it reached his waist. He wore an outlandish purple robe spangled with silver stars that Nico was quite sure would give the Aphrodite kids a heart attack. His nose was long and crooked as if it had been broken a few times, and a pair of half-moon spectacles covered some of the most piercing blue eyes Nico had ever come across.

Professor Dumbledore stared right back at him, analyzing Nico with those blue eyes. Dumbledore noticed the boy's dark eyes that were so deep they seemed to have no end, the knowledge of pain and death evident in them. The shadowy teenager seemed wise beyond his years, Dumbledore noted, which made the wizard uneasy. Who knows what lies behind those nearly black eyes? With Nico's tattered, old aviator jacket, black t-shirt and matching dark jeans and shoes, he looked menacing. The dark boy's odd and shady actions only added to his alarming demeanor.

The headmaster looked Nico directly in his eyes, "I would not dream of using such a potion on a young boy like yourself, but will you tell the truth if I don't?"

Nico pondered: Would he? No, he would not. It was impossible for Nico to reveal such secrets, nor was it his place to do so.

"Of course, Professor Dumbledore," he replied after a few moments of thinking. "As long as your questions don't interfere with the confidentiality I'm under."

"Do you have secrets to keep, Mr. di Angelo?"

"I have as many as you, I suppose," Nico replied. They both looked at each other in acknowledgement: that was quite a few secrets.

Professor Dumbledore looked troubled and The Ghost King knew he was conflicted on whether or not to use the Veritaserum. While Dumbledore was deep in thought, Nico looked around.

It was a very depressing room, with the dark shade of the walls and the same dark colored furniture. The room was like the rest of the house: old. The wallpaper flaked, leaving a mess on the floor. The furniture oozed dust, and was extremely discolored. The wizards had not been exceptionally good cleaning here either, even though the room seemed well used. Several coffee cups, plates, and something that looked like parchment littered the big table that stood in the center of the room.

Nico found his brain searching for escape routes, scouring every corner of the room for an alternative to the obvious door. It was the demigod in him, he supposed. He did not know if shadow travelling would work from inside the house with all the spells and wards surrounding it and that made him incredibly nervous. 'What if I'm on the verge of being killed and I can't escape?' Nico thought to himself. 'What can I do besides die at the hands of the descendants of Hecate?'

A voice interrupted Nico's grim thoughts. "Mr. di Angelo, I believe it best that the Veritaserum is used for everyone's safety, unfortunately. I know this is not the ideal solution, but it's the one that reveals the truth, and the whole truth. I only want to know who this boy is who managed to cause such a grand entrance and who has such unique abilities."

The Italian boy nodded grudgingly but did not fight against the old headmaster: he knew it was no good. If the teenager wanted their trust he had to earn it. It would only make him seem even more suspicious if he denied the wizards the truth. Nico knew the way he was not completely effected by their seemingly powerful spells made the magical people very anxious and apprehensive. The best thing to do was to agree to the wizard's terms.

Therefore, Nico watched Dumbledore pull the small bottle of potion from his robes and open it with no resistance. "I will not ask you any questions that will be humiliating or are unnecessary, Nico," reassured Dumbledore, as if reading Nico's mind. The son of Hades nodded in response while a flood of relief washed over him.

The white-bearded wizard pulled the cork out and put the opened bottle in front of Nico's mouth. "Now, I'm only giving you a few drops, but don't underestimate the power of a perfectly brewed truth potion," announced the headmaster. "It can make nearly any person spill all their darkest and deepest secrets." Nico did not miss the 'nearly' part, and was silently praying to every god in Olympus he fell under the category of 'nearly'.

Before Nico could even finish his thoughts, Dumbledore's gentle, wrinkly hand was under his chin, pouring some of the liquid in his mouth. A few drops of tasteless potion dripped on Nico's tongue and he prepared his mind for the questions he was about to answer, most likely, truthfully.

"You cannot feel the potion's effect until you're asked a question, which makes the serum even more dangerous," said the professor to the tense boy. The son of Hades did not know what to say, so he only nodded a curt nod as answer.

"Now, the first question I want to ask you is your name, just to be sure you told us the truth," he reassured. "What's your name, dear boy?"

Nico did not hesitate to answer truthfully, but whether it was the potion or not, he was unsure. The white-bearded wizard seemed pleased by Nico's answer though, so perhaps it was the truth serum.

The question the shadowy teen had been dreading came sooner than he thought. "And how, Nico, did you get inside this house?"

It was the moment of truth: could he resist an obviously powerful potion made to make people tell the truth? Nico had the power to block out people from prying around his brain, he could get inside of other people's heads, and he could control his dreams. These things demanded a special kind of self-control over one's brain, and his was now to be tested.


End file.
